Partial object distribution in content delivery network

• US 8,255,557 B2
• Filed: 08/24/2011
• Issued: 08/28/2012
• Est. Priority Date: 04/07/2010
• Status: Active Grant

• Current Assignee: Limelight Networks, Inc.
• Original Assignee: Limelight Networks, Inc.
• Inventors: Raciborski, Nathan F., Swanson, Wylie, Roersma, Jacob S., Black, Bryan D., Tobey, Albert P.
• Primary Examiner(s): Patel, Chirag R
• Application Number:
  US13/217,101
• Publication Number:
  US 20110307586A1
• Time in Patent Office: 370 Days
• Field of Search: 709231-232, 709217-219, 725 54- 55, 725 71- 74, 725 85- 87, 725 91- 94, 725114-116
• US Class Current: 709/231
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70

Abstract

Techniques for the distribution of content objects in a content delivery network (CDN) are disclosed. In one embodiment, a CDN distribution server detects the availability of a content object and determines whether the content object is a candidate for distribution. The distribution server may detect the availability of the content object in response to a provider making new or updated content available at a content site or a location within the CDN. The distribution server obtains identifying information for a candidate content object and determines a select portion of the content object to be distributed within the CDN. The select portion can be a predetermined number of bytes located at a predetermined position in the content object, the size and location of which may be determined according to content-specific mapping data. The distribution server may push the select portion of the content object to one or more groups of CDN edge servers absent an end-user request.

Claims

1. A method of distributing partial content objects in a content delivery network (CDN), the method comprising:

receiving at a distribution server an indication that a content object is available at a first point of presence;

obtaining from the first point of presence information relating to the content object;

determining, based on the obtained information, whether the content object is a candidate for distribution;

upon determining that the content object is a candidate for distribution;

comparing the information relating to the content object with mapping data to identify specific mapping data associated with the content object, the specific mapping data identifying a select portion of the content object;

retrieving the select portion of the content object based on the specific mapping data, the select portion including at least one of information indicative of a content type associated with the content object, or information used by an end user system to prepare to playback the content object;

determining a plurality of edge servers to receive the select portion of the content object; and

not in response to an end user request for the content object, sending the select portion of the content object to the plurality of edge servers;

receiving a request from an end-user device for the content object;

assigning the request to a selected edge server at a second point of presence; and

sending the select portion of the content object to the end-user device.

2. The method of claim 1, wherein the selected edge server is one of the plurality of edge servers.

3. The method of claim 1, wherein the selected edge server is assigned based at least partly on domain name service resolution.

4. The method of claim 1, wherein the selected edge server is assigned at least partly based on a delivery path derived from the request.

5. The method of claim 1, wherein the selected edge server is selected amongst a group of edge servers at the second point of presence.

6. The method of claim 1, wherein the selected edge server is assigned based on at least one of:

a characteristic of the content object, servers associated with a provider of the content object, predicted quality of service, capabilities of the selected edge server, and routing efficiency.

7. The method of claim 1, wherein the select portion of the content object further comprises an identifier uniquely associated with the select portion.

8. The method of claim 1, further comprising:

receiving an event from the selected edge server indicating that a partial content object associated with a content object requested by an end-user device is not available at the selected edge server; and

determining partial content objects stored at least one of the plurality of edge servers, the at least one of the plurality of edge servers being different from the selected edge server.

9. The method of claim 1, wherein the plurality of edge servers are determined based at least partly on an identified provider of the content object.

10. The method of claim 1, wherein the plurality of edge servers are determined based at least partly on characteristics of the content object.

11. The method of claim 1, wherein obtaining information relating to the content object comprises obtaining metadata for the content object.

12. The method of claim 9, wherein the select portion of the content object comprises between one and ten data bytes of the content object.

13. The method of claim 1, further comprising receiving event messages at the distribution server from a messaging system of the CDN, and wherein the indication corresponds to a new-file event or a file-update event at the first location.

14. The method of claim 1, further comprising:

detecting that at least one edge server lacks a portion of a second content object that is a candidate for positioning;

obtaining the portion of the second content object at the distribution server; and

sending the portion of the second content object from the distribution server to the at least one edge server.

15. The method of claim 14, wherein detecting that the at least one edge server lacks a portion of a second content object comprises:

requesting a sequence identifier from each edge server in the plurality of edge servers; and

comparing the sequence identifiers to an index of candidate content objects at the distribution server.

16. The method of claim 14, wherein detecting that the at least one edge server lacks a portion of a second content object is responsive to receiving a cache-miss event message generated by the at least one edge server.

17. The method of claim 1, wherein the plurality of edge servers is determined based on a geographic coverage area.

18. The method of claim 1, wherein the specific mapping data identifies a number of bytes and a position within the content object of the select portion.

25. The distribution server of claim 18, wherein the content provider information comprises a geographic area and the plurality of target edge servers is determined according to the geographic area.

27. The content distribution server of claim 17, wherein the mapping data identifies a number of bytes and a position within the content object of the select portion.

19. A content distribution server, comprising:

a messaging subsystem configured to receive event messages and to communicate with a plurality of edge servers over a content delivery network (CDN);

a memory configured to store mapping data comprising content identifiers and byte values corresponding to the content identifiers;

one or more processors configured to distribute content objects, wherein distributing content objects comprises;

determining whether the content object available at the first location is a candidate for positioning at edge servers of the CDN,

obtaining an identifier associated with the content object,

retrieving mapping data from the memory based on the identifier in response to determining that the content object is a candidate for positioning, the mapping data identifying a select portion of the content object,

obtaining from the first location the select portion of the content object based on the mapping data, the select portion including at least one of information indicative of a content type associated with the content object, or information used by an end user system to prepare to playback the content object, and

determining a plurality of edge servers to receive the portion of the content object,

sending, after receiving a request from an end-user device for the content object, the portion of the content object to the end-user device via an edge server assigned to the request,

wherein the content distribution server sends the portion of the content object to the plurality of edge servers over the CDN absent a request for the content object.

20. The distribution server of claim 19, wherein distributing content objects further comprising:

assigning the request to a CDN point of presence.

21. The distribution server of claim 20, wherein distributing content objects further comprising:

assigning the request to an edge server that is among a group of edge servers at the CDN region.

22. The distribution server of claim 20, wherein the request is assigned to a CDN region based on a delivery path included in the request.

23. The distribution server of claim 20, wherein the assigning is based at least partly on deriving a path from the user'"'"'s request.

24. The distribution server of claim 19, wherein the memory is configured to store content provider information, and wherein determining whether the content object at the first location is a candidate for positioning is based on the content provider information.

26. The distribution server of claim 19, wherein the byte values comprise a number of bytes corresponding to a client application associated with the content object.

28. A content delivery system (CDS), comprising:

a distribution server, comprising;

a messaging interface configured to detect the availability of a content object at a first location independent of a request for delivery of the content object,

an object analyzer configured to determine whether the content object is a candidate for positioning, the object analyzer further configured to obtain mapping information associated with the content object, the mapping information identifying a select portion of the content object, and to retrieve a portion of the content object from the first location based on the mapping information in response to a determination that the content object is a candidate for positioning, the portion of the content object including at least one of information indicative of a content type associated with the content object, or information used by an end user system to prepare to playback the content object, and

an edge-server group manager configured to determine a group of edge servers to receive the portion of the content object based on content provider information and, absent a request for the content object to send the portion of the content object to the group in a manner that is asynchronous to the operation of the messaging interface;

one or more request routers configured to route a request to a point of presence and to assign the request to one of a plurality of edge servers at the point of presence; and

a plurality of edge servers arranged into an edge-server a-group, each edge server in the group comprising;

a CDS interface configured to receive a group message with the portion of the content object from the distribution server,

a byte store configured to store partial content objects at the edge server, said partial content objects comprising a number of bytes that varies according to a type of a corresponding full content object,

a request interface configured to receive a content request and to send a content object to an end user computer in response to said content object request, and

a storage controller configured to store the portion of the content object received from the distribution server in the byte store and to retrieve data from the byte store in response to receiving the content request after pre-population of the byte store, the storage controller configured to generate a CDS event if it is determined that the byte store does not contain a partial content object associated with the content request.

29. The method of claim 28, wherein the mapping information identifies a number of bytes and a position within the content object of the select portion.